Rubella virus genomic RNA has conserved sequence elements both at the 5'- and the 3'-ends. The conserved sequences designated as cis-acting elements are implicated to be involved in viral replication. To test this hypothesis we ligated the cis-acting elements of Rubella virus RNA to a reporter chloramphenicol acetyltransferase (CAT) gene and established stable cell lines which transcribe a chimeric CAT RNA. The stable cells were infected with Rubella virus. In these cells we were able to demonstrate the initiation of negative-strand RNA synthesis from a chimeric CAT RNA. The initiation of negative-strand RNA synthesis was achieved only after viral infection. Studies are in progress to analyze the effect of mutations in cis-acting elements on the replication of CAT RNA. Such an analysis will help us to understand the role of cis-acting elements in rubella virus replication.